Many processes are known for treating petroleum oils and the like with alkali metal compounds or sulfides. Such processes are disclosed in U.S. Pat. Nos. 1,300,816, 1,413,005, 1,729,943, 1,938,672, 1,974,724, 2,145,657, 2,950,245, 3,112,257, 3,185,641, 3,252,774, 3,368,875, 3,354,081, 3,382,168, 3,483,119, 3,553,279, 3,565,792, 3,617,529, 3,663,431, 3,745,109, 3,787,315, 3,788,978, 3,816,298, 4,003,823, 4,007,109, 4,018,572, and 4,119,528.
For example, U.S. Pat. No. 3,252,774 discloses a process for cracking liquid hydrocarbons to produce hydrogen-containing gases by contacting the feedstock with a melt of an alkali metal compound (e.g., the sulfides), at temperatures between about 800.degree. and 1800.degree. F. in the presence of steam.
U.S. Pat. No. 3,617,529 discloses removing elemental sulfur from petroleum oil by contacting the oil at ambient temperature with an aqueous solution containing sodium hydrosulfide alone or in combination with sodium hydroxide and ammonium hydroxide. The aqueous solution and oil are separated, and the aqueous solution is treated to free the sulfur from the polysulfides that are formed during the contacting step.
U.S. Pat. Nos. 3,787,315 and 3,788,978 disclose processes for desulfurizing petroleum oil. The oil is contacted with an alkali metal or alloy in the presence of hydrogen to form a sulfide, thereby desulfurizing the oil. The sulfide is separated from the oil by treating with hydrogen sulfide, and the separated monosulfide is treated with a sodium polysulfide to form a polysulfide of lower sulfur content, which is then electrolyzed to produce sodium.
U.S. Pat. No. 3,816,298 discloses a two-stage process for upgrading (partially desulfurizing, hydrogenating, and hydrocracking) heavy hydrocarbons (e.g., vacuum residuum) into liquid hydrocarbon products and a hydrogen-containing gas. In the first stage, the hydrocarbon feed is contacted with a gas containing hydrogen and carbon oxide in the presence of any of numerous catalysts, including alkali metal sulfides and hydrosulfides. The pressure must be above 150 psig and the average temperature between about 700.degree. and 1,100.degree. F. An example shows feeding steam (as well as hydrogen and carbon oxides) to the first stage with K.sub.2 CO.sub.3 catalyst, at 340 psig and 910.degree. F. A by-product, solid carbonaceous material, is deposited on the catalyst and a portion of the catalyst is sent to the second reaction stage where it is contacted with steam, at a pressure above 150 psig and an average temperature above 1,200.degree. F.
U.S. Pat. No. 4,003,823 discloses another process for upgrading heavy hydrocarbons, by contacting them with alkali metal hydroxides, at hydrogen pressures of from about 500 to 5,000 psig and temperatures of from about 500.degree. to 2,000.degree. F. Hydrogen sulfide may be added to the products withdrawn from the reaction zone to convert alkali metal sulfides formed in the reactor to hydrosulfides, as the first step in regenerating the alkali metal hydroxides.
U.S. Pat. No. 4,018,572 discloses a process for desulfurizing fossil fuels by contacting the material with aqueous solutions or melts of alkali metal polysulfides to form salts with higher sulfur content, which are decomposed to regenerate the polysulfides of reduced sulfur content.
Finally, U.S. Pat. No. 4,119,528 discloses another process for treating heavy carbonaceous feedstocks, using potassium sulfide and hydrogen pressure of from about 500 to 5,000 psig and temperatures of from 500.degree. to 2,000.degree. F. The products are desulfurized, lower-boiling oils and potassium hydrosulfide, which may be converted back to potassium sulfide. The potassium sulfide may be charged to the reactor as such or made in situ by reacting various potassium compounds with sulfur compounds, such as hydrogen sulfide. The potassium sulfide may also be made by reducing potassium compounds, such as the hydrosulfide or the polysulfides, with reducing agents, such as hydrogen. The sulfide may also be made by the high temperature steaming of potassium hydrosulfide. Preferably, a mixture of potassium and sodium sulfides is used because the sodium sulfide acts as a "getter" for the hydrogen sulfide produced during reaction that would otherwise react with the potassium sulfide to form "inactive" potassium hydrosulfide.
None of these discloses the use of empirical hydrates of alkali metal hydrosulfides, sulfides, or polysulfides to hydrotreat (e.g., hydrogenate and hydrocrack) carbonaceous material.